Causal Language for Studies Using Difference-in-Differences Analyses

Many clinical investigations are intended to evaluate or demonstrate causal relationships (eg, the effect of a treatment or other intervention on patient outcomes), whether using information from well-designed randomized clinical trials, leveraging observational data with suitable methods, or combining the 2 approaches. Evaluating and communicating the degree to which a given study supports a causal conclusion can be complex, typically involving both clinical and methodological considerations, a...